It's not enough for network administrators to have a system that detects only the most common or oldest viral forms. In our tests VirusWall was the only product to spot hostile applets. In addition, we found the product to be on the cutting edge of malicious-code detection, spotting even the most recent developments, including threats to VBScript, JavaScript, HTML infectors, MS-Access macros and MS-PowerPoint macros. A VirusWall module is assigned applets and compares them to a known signature database for an added level of protection and validation.

Once VirusWall detected a virus, it was the only product we tested that attempted to clean the infected file. When it was successful, the newly uninfected file was sent to the appropriate recipient. If VirusWall was unable to remove the infected file, the message was deleted and an e-mail message was transmitted to the sender, recipient and network administrator notifying them that the message was undeliverable because of an infection.

We appreciated VirusWall's ability to keep or remove attachments selectively. When one file out of 10 was infected, VirusWall delivered the uninfected attachments, and cleaned or removed the infected attachment.

Also of note is VirusWall's expansive dictionary of compression routines, which was more extensive than any other product we tested. It quickly processed each of the 12 encoding/compression formats we threw at it and detected the virus-infected files within.

However, our tests showed that VirusWall isn't perfect. We were able to sneak viruses past its scanning algorithms using a few methods. First, we were able to uuencode a raw file and paste the encoded text into the body of an e-mail message. Our mail client recognized and decoded the message, presenting us with a live virus, ready to run on our desktop. VirusWall seemed to look for viral content as attachments, but not in the body of a message. Second, VirusWall did not notice any Macintosh or Linux viruses. And even with its high marks on our detection tests, VirusWall failed to recognize several viruses and Trojan horses picked up by our client-side scanners.

During our testing, we witnessed the arrival of a new virus called "happy99.exe." This program was first detected in early January. A widespread newcomer aimed at crippling Windows desktops, it attempts self-propagation by hiding in e-mail messages. Already, there have been several security advisories and user warnings on the Internet about happy99.exe. The recent appearance of this virus allowed us to test how quickly the vendors were able to incorporate scan/clean strings into their products. VirusWall's pattern file detected the strain in its second February pattern update.

Trend Micro's InterScan VirusWall is a robust package that offers more than e-mail virus protection; it can tackle your FTP, HTTP and SMTP traffic with equal aplomb. Dynamic and current, it will provide you with the extra protection necessary to secure your network.